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The objective of this document is to facilitate consistency throughout the state in managing IDW, remediation environmental media and debris potentially contaminated with hazardous waste. While this guidance is applicable to locations that do not come under the “area of contamination” (AOC) policy or have not had an AOC designated, AOC considerations are discussed in this document to better clarify the full range of options available when considering investigation and remediation questions should an AOC be appropriate. This document is not meant for use to develop cleanup plans or criteria. This document was written for environmental investigation and remediation professionals for general guidance. Always contact your DEQ remediation project manager before finalizing the details of your individual remediation projects.

What is Investigation-Derived Waste (IDW)?

IDW is a subset of remediation wastes. IDW is waste that is generated in the process of investigating or examining a known or potentially contaminated site. It includes solid and hazardous waste, media (including groundwater, surface water, soils, and sediments) and all debris that contains listed hazardous wastes or exhibits a characteristic of a hazardous waste. It also includes media and debris that is not hazardous but is contaminated with hazardous constituents. Not all IDW is hazardous waste.

IDW includes wastes that are generated from field investigation activities, typically approved and overseen by the Nebraska Department of Environmental Quality (NDEQ) or the U. S. Environmental Protection Agency (EPA), that are specifically designed to determine the nature and extent of contamination. IDW will normally be generated during the site assessment, remedial investigation, and/or feasibility study stage of a cleanup project. IDW is the waste generated from an activity related to determining the nature and extent of contamination as well as the preparation or examination of the site for future remediation. Such wastes can include, but are not limited to: drilling mud, cuttings, and purge water from test borings and well installation; purge water, soil and other materials from collection of samples; contaminated personal protective equipment (PPE), and solutions used to decontaminate non-disposable protective clothing and sampling equipment; and equipment used during field investigation activities.

IDW does not include wastes that are generated from the removal or displacement of environmental media or debris as a result of other related remediation activities (these would be remediation wastes) or activities not related to remediation such as geotechnical investigation for building construction. The generator can usually dispose of non-hazardous IDW, depending on its physical state and health–based characteristics, as any other solid waste. However, federal, state, and local waste, air, and water regulations apply. For example, most non-hazardous media cannot be disposed by open burning. As another example, land application of contaminated media is regulated in Nebraska and is usually not allowed except to permitted municipal solid waste (MSW) landfills.

Is The Waste Hazardous?

Environmental media is not, of itself, a waste. It can, however, contain listed hazardous wastes or enough hazardous constituents that it exhibits a characteristic of a hazardous waste. If the media will be actively managed and it contains listed hazardous waste or exhibits a characteristic of hazardous waste, it must be managed as a hazardous waste.

There may be circumstances where pre-existing sampling data may be used to make a hazardous waste determination. Factors such as the age of the extant sampling data, potential for changed conditions, and whether the sampling data used is representative of the IDW in question must be considered. For further information regarding hazardous waste determinations see the DEQ’s Environmental Guidance Document “Waste Determinations & Hazardous Waste Testing”.

Active Management and Point of Generation
The concept of “active management” as applied to IDW or remediation waste is associated with environmental media or debris. If media or debris is being displaced on a site due to activities related to contamination investigation or remediation, the NDEQ considers such activities as active management under the waste regulations. Activity not related to investigation or remediation is not considered “active management” under the waste regulations. For example, routine trench or foundation excavation spoils that are generated at a site that is not a remediation or investigation activity site, or are not related to remediation or investigation activities, are not considered a waste unless it is intended for disposal. Such spoils could normally be replaced in the excavation. In investigation or remediation activities, the point of generation (POG) of waste is where or when the media or debris is excavated or investigation or remediation related wastes are either created or rendered spent. For example, for PPE the POG is generally the location where the equipment is determined to be no longer usable. Sampling gloves are routinely rendered “spent” between sampling events. These gloves are considered waste when they are removed.Pre-Characterized Sites.
When a site can be adequately pre-characterized as not contaminated with listed hazardous waste nor with characteristic hazardous waste, IDW from this site does not require management as hazardous waste. Examples of this type of IDW include: cuttings and purge water from wells or piezometers located a significant distance from known contamination that are being drilled to fully determine hydrologic conditions or gradient, cuttings from an uncontaminated and unsaturated zone above suspected groundwater contamination; etc.

However, if the pre-characterization is proven to be wrong by subsequent investigation, incorrect management of the IDW may result in an expansion of the scope of the cleanup or remediation, since contamination may have been spread. This could result in an enforcement action. To avoid this possibility, the department recommends that IDW be containerized and managed according to this guidance, pending the completed hazardous waste determination for any portion of a site with limited or poor historical data. How to Manage IDW or Remediation Waste.
Often, once IDW or remediation waste is generated it needs appropriate management before a hazardous waste determination is completed (usually due to the laboratory turnaround time for analysis of field samples). Unless the area where the IDW or remediation waste was generated was pre-characterized as not containing hazardous waste, the waste should be managed as follows:

Disposable Personal Protective and Sampling Equipment:

Containerize when generated. This waste is a solid waste and could, therefore, be a hazardous waste. Personal protective and sampling equipment becomes a hazardous waste at the time it is disposed if it is contaminated with any listed hazardous waste. According to the “Mixture Rule” (See Title 128- Nebraska Hazardous Waste Regulations, Chapter 2, §005.02), any mixture of solid waste and listed hazardous waste becomes a listed hazardous waste. Although unlikely, this waste may also be a hazardous waste if it has become contaminated with enough hazardous constituents to exhibit a characteristic of a hazardous waste. (Spent filters are examples of IDW or remediation waste that are often characteristic for toxicity.)

Containerize when generated pending characterization. If the solid media contains a listed waste, you must obtain a determination by the department’s Waste Management Division that the waste no longer “contains” listed waste before it can be considered a non-hazardous waste and disposed of as such. (See the EPA’s “contained-in” policy.) The department recognizes that circumstances will vary from site to site.

Generally speaking, drill cuttings/soil/sediment may be returned to the site of original removal if the media is a non-hazardous waste and is below the EPA Regional Screening Levels (RSLs) or the Nebraska Voluntary Cleanup Program (VCP) Remediation Goals (RGs) for all constituents of concern. IDW or remediation waste drill cuttings/soil/sediment must not be allowed to be used as fill on other areas of the site or off site unless the media is not mixed with other solid wastes and does not have the potential to cause contamination that may threaten human health or the environment. Merely being below appropriate PRG or VCP Lookup Table Values does not necessarily mean the media won’t have the potential to cause contamination that may threaten human health or the environment. There might also be situations where “landfarming” of some types of contaminated soils is appropriate. For example, media contaminated solely with petroleum fuels can often be landfarmed successfully and safely. Contact the NDEQ Waste Management Section for more information.

If you have questions about how to implement this section for your particular situation, contact the department for clarification and assistance. (Example: Test pits might be the most convenient sampling methodology, but they generate a great deal of material that must be managed and should be used only after the depth to ground water has been established.)

Purge and Development/Decontamination Water:

Containerize this material when it is generated. If the water is a listed or is a characteristic hazardous waste it may not be discharged to the ground or back to the well. If analysis of the water determines that it is not hazardous waste and it meets ground water standards found in Title 118 – Ground Water Quality Standards and Use Classification, VCP RGs, or health-based standards, the water may be poured on the ground at or near the point of generation, but not back to the well. If the water contains a listed waste, you must obtain a determination by the department that the waste no longer “contains” listed waste before it can be disposed of as a non-hazardous waste. (See the EPA’s “contained-in” policy.)

Discharging this material to surface water or drainages should be avoided because of stringent aquatic life water quality standards.

Where there is prior approval by the affected Publicly Owned Treatment Works (POTW) (Municipal Wastewater Treatment Plant) Facility, discharges directly through an on-site sanitary sewer system to a POTW may be allowed. (Note: The water cannot be transported to a Nebraska POTW if it is a listed or characteristic hazardous waste. Nor can listed or characteristic hazardous waste water be transported to another site that has a sanitary sewer connection to a Nebraska POTW.)

The department understands that there may be a large amount of decontamination water to containerize for analysis and characterization; therefore we recommend the initial generation of decontamination water be minimized.

Water generated from dewatering IDW must be managed as a separate waste. Containerize the water upon generation. A separate waste determination is required. If analysis of the water determines that is not hazardous waste and it meets ground water standards found in Title 118 – Ground Water Quality Standards and Use Classification, VCP Lookup Table values, or health based standards, the water may be poured on the ground at or near the point of generation. If the water contains a listed waste, you must obtain a determination by the department that the waste no longer “contains” listed waste before it can be disposed of as a non-hazardous waste. (See EPA’s “Contained-In” policy)

Miscellaneous Waste Issues:

The disposal of waste in unpermitted landfills is prohibited. In other words, you can’t put waste in or on the ground or put it back in or on the ground if it’s not a permitted landfill. There may be times during investigation or remediation activities when excavation uncovers materials that might have been improperly disposed. In addition to excavating items that were improperly disposed, there may be times when random non-media items are excavated that had a legitimate reason for being in the ground. Generally speaking, if waste-like items are excavated, they must not be placed back in the ground. These items should be sent to a municipal solid waste landfill if determined to be a non-hazardous waste and can pass the “paint filter” test. Examples:

If you excavate an abandoned pipe or cable section, you should not re-bury that piece. There is no need to remove the remaining pipe or cable that was not excavated.

If you come upon a dumpsite and determine the waste was placed after October 1, 1993 (when the solid waste regulations became effective in Nebraska), all the waste might need to be removed to a properly permitted landfill. If the landfill site was closed prior to October 1, 1993, then only the waste items removed during excavation need to be sent to a properly permitted solid waste landfill. The unexcavated wastes can be recovered.

If you come upon “free-product” material, you should consider this material to be a waste. It should not be left on site. Waste determination and proper waste management would be required.

Use As Fill:

Nebraska Title 132 – Integrated Solid Waste Management Regulations, Chapter 1, §041 defines “fill” as solid waste that consists only of one or more of the following: sand, gravel, stone, soil, rock, brick, concrete rubble, asphalt rubble, or similar material. If excavation uncovers buried material that appears to meet the above definition, the NDEQ would normally allow such material to be replaced in the excavation if it is not otherwise hazardous. If the “fill” were mixed with other types of wastes not mentioned above it would not meet the above definition. This would be evidence that the location might be a former landfill. In some cases, excavation spoils might be able to be used elsewhere on site or at another site. Title 132, Chapter 2, §002.01 and §002.01A allow the use of fill for certain land improvement purposes provided the wastes used in these activities are not mixed with other wastes and do not have the potential to cause contamination that might threaten human health or the environment.

Hazardous IDW or Remediation Waste Placed on the Ground.

Hazardous IDW or remediation waste placed on the ground creates a regulated unit and constitutes a solid waste management unit (SWMU) that might be subject to RCRA permitting or closure requirements. Placement on the ground occurs even when the IDW or remediation waste is placed on plastic sheets or concrete pads. Note that the Area of Contamination Policy can change this assessment, but only when and where an AOC has been formally declared.Storage In Containers
Hazardous waste storage in containers must meet the requirements of Title 128 - Nebraska Hazardous Waste Regulations, Chapter 9 or 10 (whichever applies), or, if applicable, a RCRA hazardous waste storage permit. Hazardous IDW or remediation waste must be stored and managed as a hazardous waste because returning it to a SWMU might exacerbate the contamination cleanup regulatory issues. Facilities will need a hazardous waste storage permit after accumulating hazardous IDW or remediation waste for longer than;

90 days for Large Quantity Generators (LQGs) (See Title 128, Chapter 10), or

180/270 days for Small Quantity Generators (SQGs) (See Title 128, Chapter 9).

Hazardous waste accumulation is limited to the generator’s accumulation timeframe. However, a special one-time 30-day extension approval may be requested from the department, if the generator can justify that an additional 30 days is essential. This request must be made in writing, within the generator’s allowable accumulation timeframe. Already permitted facilities may need to modify their current RCRA permit to store the waste. If a remedy is chosen to treat the waste in tanks or containers and that remedy cannot effectively treat the hazardous IDW, it must be properly disposed of within the generator’s accumulation timeframe or as delineated in a RCRA permit.

If only conditionally exempt small quantity generator (CESQG) amounts are involved, then the waste may be disposed to a permitted municipal solid waste landfill with prior approval by the landfill. In this case, no more than 19.5 kg (43 pounds) of the CESQG waste may be sent to the landfill on any one day. Such wastes must be able to pass the “paint-filter” test. Check with your local landfill, waste handler or local health department prior to disposal, as local city or county ordinances may be more stringent.
Certain liquid wastes may be sent to a publicly owned treatment works (POTW) via an onsite sanitary sewer with prior approval by the POTW.

The generator of IDW or remediation waste must meet all SQG or LQG generator requirements as appropriate.

Non-hazardous IDW.

Options follow:

Return water media to the ground at/near generation point if it meets certain criteria as explained above. Site specifics must be considered (e.g. ground water quality, distance to surface water, etc.). If the liquid is non-hazardous it could be transported to a POTW, pending acceptance from the POTW to take the liquid. Non-media IDW or remediation waste must be disposed off-site to a proper facility.
Non-hazardous environmental media should be disposed in a permitted landfill or properly treated on or off site. If the levels of contamination in the soil are protective of human health and the environment it may be allowed to be used as fill, as discussed above.

Area of Contamination Policy Considerations
As stated previously, this guidance document generally applies to non-AOC sites. This section is intended as a source of additional information should conditions warrant application of the AOC policy. AOCs are certain discrete areas of generally dispersed contamination that can be equated to a RCRA landfill and where movement of hazardous wastes within those areas would not be considered land disposal and would not trigger the RCRA land disposal restrictions. The AOC policy generally involves the concept of “placement.” “Placement” of hazardous waste into or on a landfill or other land-based unit is considered land disposal, which triggers the land disposal restrictions and might trigger other RCRA requirements including permitting, closure, and post-closure regulations and procedures. Generally, “placement” does not occur when waste is consolidated within an AOC, when it is treated in situ, or when it is left in place. “Placement” does occur if wastes are moved from one AOC to another (e.g., for consolidation) or when waste is actively managed (e.g., ex situ treatment) within or outside the AOC and returned to land.

AOC Factors.

Only the EPA or NDEQ can formally designate an AOC in Nebraska. The lateral extent of an AOC must be limited to the actual area of contiguous, but not necessarily homogenous, contamination. Hazardous waste placed outside an AOC would be considered land disposal and might be subject to RCRA corrective action. AOCs do not include adjacent areas used to implement response activities. The AOC policy does not include contaminated ground water or surface water that may be associated with the land-based source of hazardous waste.

AOC Designation.

The department can designate an AOC upon a formal request based on:

Data presented to the department,

Discrete areas of contamination,

Approval of an adequate, comprehensive sampling plan,

A workplan describing hazardous waste activities to be performed in the AOC, and,